Intro to Coffee Roasting Week 2: Green Coffee Density and Screen Size

Week 2 of my intro to coffee roasting study, working through Lesson 2: density, screen size, and uniformity of green coffee. This is an unscripted study session, so I stop to think out loud, get a few things wrong, and sort them out as I go. We look at how density is measured at home with a one liter container and a scale, the difference between free fall and packed density, and why altitude and cell wall hardness make dense beans need more early heat while soft beans scorch more easily. Then we go through screen size, why mixed bean sizes roast unevenly, and how to check uniformity with sieves, or just a ruler and white paper if you don't own any. The last stretch is a quick read through some coffee industry news: roasting consistency at scale, a roaster's wholesale deal, Colombian competition lots, Cameroon farmer compensation, and ports and supply chains. Chapters 0:00 Starting up 1:30 Week 2 Lesson 2 overview 2:04 Why density is the roaster's number 3:56 Altitude, cell walls, and heat 5:58 Measuring density at home 8:49 Screen size 10:20 Why uniformity matters in roasting 12:30 Assessing uniformity with sieves 14:53 Logging measurements in the spreadsheet 16:11 Key takeaways 17:37 Coffee industry news 22:32 Wrap up